Liquid crystal display

ABSTRACT

A liquid crystal display is provided. Red, blue and green pixels are sequentially arranged in a row direction. The red pixels and the green pixels are alternately arranged in a column direction and the blue pixels are arranged in the column direction. Four red and green pixels surrounding adjacent two blue pixels in neighboring two pixel rows face each other. Pixel electrodes and a common electrode have cutouts. A ratio of horizontal to vertical of each pixel is equal to 2:3. In this structure, a PenTile Matrix driving provides high resolution images, and the control of the arrangement of the liquid crystal molecules by the cutouts of the pixel electrode and the common electrode and the common electrode provides wide viewing angle.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a liquid crystal display and, moreparticularly, to a liquid crystal display with a PenTile pixelarrangement for displaying high resolution images.

(b) Description of the Related Art

Generally, a liquid crystal display (LCD) includes two panels withelectrodes for generating electric fields, and a liquid crystal layersandwiched between the two panels. Different voltages are applied to theelectrodes to form electric fields, which re-orients the liquid crystalmolecules in the liquid crystal layer to control the lighttransmittance, thereby displaying the desired images.

The LCD includes a plurality of pixels with pixel electrodes and red,green and blue color filters. The pixels are driven by signalstransmitted thereto via signal wires. The signal wires include scanningsignal lines or gate lines for carrying scanning signals, and imagesignal lines or data lines for carrying image signals. A thin filmtransistor (TFT) connected to one gate line and one data line are formedat each pixel. The TFT controls the image signals transmitted to thepixel electrode provided in the pixel.

There are several types of arrangements for the red, green and bluecolor filters at the respective pixels. Among them are a stripe typewhere the color filters of the same color are arranged along therespective pixel columns, a mosaic type where the red, green and bluecolor filters are sequentially arranged in row and column directions,and a delta type where the pixels are arranged in zigzags in the columndirection, and the red, green and blue color filters are sequentiallyarranged in the pixels. In the case of the delta type, the three unitpixels with the red, green and blue color filters form one dot, whichclosely express a circle or a diagonal line on the display screen.

The ClairVoyante Laboratories has proposed a pixel arrangement calledthe “PenTile Matrix™,” which is advantageous in displaying highresolution images while gives minimized design cost. In the pixelarrangement, the blue unit pixel is common to two dots, and theneighboring blue pixels receive the data signals from one data drivingIC while being driven by two different gate driving ICs. With the use ofthe PenTile Matrix pixel arrangements the resolution of the ultraextended graphics array (UXGA) level can be realized by way of a displaydevice of the super video graphics array (SVGA) level. Furthermore, thenumber of relatively expensive data driving ICs is decreased althoughthe number of relatively cheap gate driving ICs is increased. Thisminimizes the production cost for the display device.

However, in the above-described LCD, the blue pixel has a shape of adiamond and correspondingly, the signal lines for carrying the datasignals are elongated. Consequently, the signal delay of the datasignals to be transmitted to the pixels becomes severe such that thedisplay characteristic becomes non-uniform. Therefore, it is difficultto apply the PenTile Matrix pixel arrangement to large LCDs.Furthermore, a blue pixel enclosed by the red and green pixels occupiestwo pixel columns and the blue pixel differs in size from the red orgreen pixel, which makes it very difficult to form a storage capacitorrequired for the LCD.

The data lines for transmitting data signals to the red or green pixelsor two gate signal lines become close to each other so that the signallines is liable to be short-circuited to reduce the production yield andthe intervention of the neighboring data lines deteriorates the displaycharacteristic. Furthermore, since the neighboring blue pixels aredriven by one driving IC, the data driving ICs are required to beprovided at both sides of the display area. Therefore, the displaydevice becomes enlarged and it becomes difficult to form repair linesfor repairing disconnection and short circuit at the periphery of thedisplay area. The inversion for preventing the deterioration of theliquid crystal gives irregular polarity to the red, green and bluepixels to generate flicker and to differentiate the brightness of thepixel columns, thereby deteriorating the image quality of the displaydevice.

Meanwhile, in order to increase the resolution, the LCD having a PenTileMatrix pixel arrangement utilizes rendering.

SUMMARY OF THE INVENTION

It is a motivation of the present invention to provide a thin filmtransistor array panel for a liquid crystal display which involvesexcellent display characteristic while preventing the signal wirecomponents at the neighboring pixels from being short-circuited.

It is another motivation of the present invention to provide a thin filmtransistor array panel for a liquid crystal display which involvesexcellent display characteristic while obtaining the required storagecapacitance in a stable manner.

It is still another motivation of the present invention to provide athin film transistor array panel for a liquid crystal display whichinvolves excellent display characteristic with a minimized panel sizewhile having repair lines for repairing possible disconnection orshort-circuiting of the signal wire.

It is still another motivation of the present invention to provide athin film transistor array panel for a liquid crystal display which canmake the inversion in a regular manner.

It is still another motivation of the present invention to provide athin film transistor array panel for a liquid crystal display which canbe well adapted for the rendering driving technique of displaying imagesat high resolution.

According to one aspect of the present invention, a thin film transistorarray panel is provided, which includes: an insulating substrate; aplurality of gate lines carrying scanning signals, formed on theinsulating substrate, and proceeding in a transverse direction; aplurality of data lines carrying image signals, proceeding in alongitudinal direction to intersect the gate lines, and insulated fromthe gate lines; a plurality of pixel electrodes formed in respectivepixels defined by intersections of the gate lines and the data lines andreceiving the image signals; and a plurality of thin film transistorsformed in the pixels and having gate electrodes connected to the gatelines, source electrodes connected to the data lines, and drainelectrodes connected to the pixel electrodes, wherein a ratio ofhorizontal to vertical of each pixel is substantially equal to 2:3.

The pixel electrodes preferably overlap previous gate lines fortransmitting the scanning signals to previous adjacent pixel rows toform storage capacitors. Alternatively, the thin film transistor arraypanel further includes a plurality of storage electrode lines separatedfrom the gate lines, formed of the same layer as the gate lines, andoverlapping the pixel electrodes to form storage capacitors. The thinfilm transistor array panel may further include a protective layerformed between the pixel electrodes and the gate lines and the datalines, made of acryl-based organic insulating material or chemical vapordeposited insulating material having a dielectric constant equal to orless than 4.0, and having a plurality of contact holes for electricallyconnecting the pixel electrodes to the drain electrodes. The data linesmay have a triple-layered structure including an amorphous siliconlayer, an ohmic contact layer, and a metallic layer. The pixelelectrodes may have cutouts, and a data pad for receiving data signalsfrom an external device may be connected to each data line.

According to another aspect of the present invention, a liquid crystaldisplay is provided, which includes: a first insulating substrate; aplurality of gate lines carrying scanning signals, formed on the firstinsulating substrate, and proceeding in a transverse direction; aplurality of data lines carrying image signals, proceeding in alongitudinal direction to intersect the gate lines, and insulated fromthe gate lines; a plurality of pixel electrodes formed in respectivepixels defined by intersections of the gate lines and the data lines andreceiving the image signals; and a plurality of thin film transistorsformed in the pixels and having gate electrodes connected to the gatelines, source electrodes connected to the data lines, and drainelectrodes connected to the pixel electrodes; a second insulatingsubstrate facing the first insulating substrate; a black matrix formedon the second insulating substrate; red, green and blue color filtersformed on the black matrix and provided at the respective pixels; acommon electrode formed on the color filters; and a liquid crystal layersandwiched between the pixel electrode and the common electrode, whereinred, blue and green pixels are sequentially arranged in a row direction,the red and the green pixels are alternately arranged in a columndirection, the blue pixels are repeatedly arranged in the columndirection, four red and green pixels surrounding adjacent two bluepixels in neighboring two pixel rows face each other, and a ratio ofhorizontal to vertical of each pixel is equal to 2:3.

Preferably, each pixel electrode has a first cutout, the commonelectrode has a plurality of second cutouts, and each pixel ispartitioned into a plurality of domains by the first and the secondcutouts. Liquid crystal molecules contained in the liquid crystal layermay be aligned perpendicular to the first and the second substrates inabsence of electric field between the pixel electrodes and the commonelectrode.

The liquid crystal display may further include a protective layer formedbetween the pixel electrodes and the gate lines and the data lines andhaving a plurality of contact holes for electrically connecting thepixel electrodes to the drain electrodes, the drain electrodesoverlapping the second cutouts at least at the contact holes.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention, and many of the attendantadvantages thereof, will be readily apparent as the same becomes betterunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings in which likereference symbols indicate the same or the similar components, wherein:

FIG. 1 is a layout view of pixel arrangement of an LCD with a TFT arraypanel according to a first embodiment of the present invention;

FIGS. 2 and 3 are sectional views of the TFT array panel for the LCDshown in FIG. 1 taken along the lines II-II′ and III-III′, respectively;

FIG. 4 is a layout view of a connection configuration of a TFT arraypanel for an LCD according to a second embodiment of the presentinvention;

FIG. 5 is a sectional view of the configuration shown in FIG. 4 takenalong the line V-V′;

FIGS. 6 to 8 illustrate inversion schemes and connections of signallines therefor of an LCD according to third to fifth embodiments of thepresent invention;

FIGS. 9 and 10 illustrate column inversion and double-dot inversion forthe LCD according to the fourth embodiment of the present invention,respectively;

FIGS. 11 and 12 are layout views of a cross-connection of data lines foran LCD according to the third to the fifth embodiments of the presentinvention.

FIG. 13 is a layout view of connections and cross-connections of datalines on the TFT panel for the LCD according to the third to the fifthembodiments of the present invention;

FIG. 14 is a layout view of an LCD with a PenTile Matrix pixelarrangement according to a sixth embodiment of the present invention;

FIG. 15 is a layout view of an LCD according to a seventh embodiment ofthe present invention; and

FIG. 16 is a sectional view of the LCD shown in FIG. 15 taken along theline XVI-XVI′.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the inventions are shown. The present invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein.

In the drawings, the thickness of layers and regions are exaggerated forclarity. Like numerals refer to like elements throughout. It will beunderstood that when an element such as a layer, film, region, panel orsubstrate is referred to as being “on” another element, it can bedirectly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present.

FIG. 1 is a layout view of a pixel arrangement of an LCD according to afirst embodiment of the present invention, and FIGS. 2 and 3 aresectional views of the TFT array panel shown in FIG. 1 taken along theline II-II′ and the line III-III′, respectively. FIG. 2 specificallyillustrates a pixel area and a pad area and FIG. 3 specificallyillustrates a connection configuration C where the data lines fortransmitting data signals to the two blue pixel neighbors B1 and B2 areconnected to each other by one pad.

Referring to FIG. 1, an LCD according to a first embodiment of thepresent invention includes a plurality of red, blue and green pixels R,B1, G, R, B2, and G arranged in a matrix. A pixel row includessequentially and repeatedly arranged red, blue and green pixels R, B1,G, R, B2 and G and a pixel column includes the pixels representing oneof red, green and blue colors. Alternatively, a pixel column includesalternately arranged red and green pixels R and G and the red and thegreen pixels R and G in a row are such that they are opposite withrespect to the blue pixels B1 or B2.

As shown in FIG. 1, a plurality of gate lines (or scanning lines) 121 aand 121 b for carrying scanning signals or gate signals, which extend inthe row direction, are provided at the respective pixel rows. Aplurality of data lines 171 for carrying data signals are provided atthe respective pixel columns. The data lines 171 proceed in the columndirection such that they cross over the gate lines 121 a and 121 b todefine pixel areas and are insulated from each other.

A TFT is formed at each cross point of the gate lines 121 a and the datalines 171. The TFT includes a gate electrode 123 connected to the gateline 121 a, a source electrode 173 connected to the data line 171, adrain electrode 175 facing the source electrode 173 with respect to thegate electrode 123, and a semiconductor layer 154. A plurality of pixelelectrodes 190 are provided at respective pixels and electricallyconnected to the gate lines 121 a and the data lines 171 through theTFTs.

The pixel electrodes 190 for the blue pixels B1 and B2 in two pixel rowneighbors are connected to each other by first and second pixelelectrode connections 901 and 902, which are alternately arranged in therow direction. One TFT is assigned to two blue pixels B1 or B2 adjacentin the column direction in an alternate manner. For example, the oddpixels in the B1 pixel columns include the TFTs, and the even pixels inthe B2 pixel columns include the TFTs. The first and the secondconnections 901 and 902 overlap the same gate line 121 a. Alternatively,the first connections 901 overlap the odd gate lines, while the secondconnections 902 overlap the even gate lines. In this case, the first andthe second connections 901 and 902 may overlap the gate lines fortransmitting the scanning signals to the pixels belonging thereto.

Each pixel area has a shape of rectangle having 2:3 horizontal tovertical ratio. The ratio is determined in consideration that two bluepixels form one dot in association with the pair of red and green pixelsarranged at the left and the right sides thereof in an alternate manner.

The TFT array panel for the LCD with the above-described pixelarrangement will be specifically described with reference to FIGS. 1 to3.

Referring to FIGS. 1 to 3, the TFT array panel according to the firstembodiment of the present invention includes an insulating substrate 110and a gate wire formed on the insulating substrate 110 preferably madeof metal or conductive material such as Al, Al alloy, Mo, Cr, Ta, Ag,and Ag alloy. The gate wire includes a plurality of scanning signallines or gate lines 121 a and 121 b proceeding in a transverse directionin pairs, a plurality of gate electrodes 123 for TFTs being parts of thegate lines 121 a, a plurality of connections 127 for interconnecting therespective pairs of gate lines 121 a and 121 b, and a plurality of gatepads 125 connected to one ends of the gate lines 121 a for receivingscanning signals from an external device and transmitting the receivedsignals to the gate lines 121 a. The gate wire 121 a, 121 b, 123, 125and 127 overlaps pixel electrodes 190 of the neighboring pixel rows toform storage capacitors with storage capacitances enhancing chargestoring capacity of the pixels, which will be described later. In casethe desired storage capacitance is not obtained, a storage wire formedof the same layer as the gate wire 121 a, 121 b, 123, 125 and 127 isprovided such that it overlaps the pixel electrodes 190.

Meanwhile, a plurality of first pad connections 122 formed of the samelayer as the gate wire 121 a, 121 b, 123, 125 and 127 are provided. Thefirst pad connections 122 are placed in an area C external to a displayarea D and interconnect the data lines 171 for the neighboring columnsof the blue pixels B1 and B2 to one data pad 179. The display area Drefers to an area displaying images and including the sets of red, blueand green pixels R, B1, G, R, B2 and G.

The gate wire 121 a, 121 b, 123, 125 and 127 may have a single-layeredstructure, a double-layered structure, or a triple-layered structure. Incase the gate line wire has a double-layered structure, it is preferablethat one layer is made of a low resistance material and the other layeris made of a material having a good contact characteristic with othermaterials. Examples are Cr/Al (or Al alloy) layers and Al/Mo layers.

A gate insulating layer 140 preferably made of silicon nitride (SiNx) isformed on the gate wire 121 a, 121 b, 123, 125 and 127 and the padconnections 122.

A semiconductor layer 154 preferably made of hydrogenated amorphoussilicon is formed on the gate insulating layer 140, and an ohmic contactlayer 163 and 165 preferably made of amorphous silicon heavily dopedwith n type impurities such as P is formed on the semiconductor layer154.

A data wire preferably made of a conductive material such as Al, Alalloy, Mo, MoW alloy, Cr, Ta, Cu and Cu alloy is formed on the ohmiccontact layer 163 and 165. The data wire includes a plurality of dataline units and a plurality of drain electrodes 175. Each data line unitincludes a data line 171 proceeding in the longitudinal direction, aplurality of source electrodes 173 of TFTs connected to the data line171, and a plurality of data pads 179 connected to one ends of the datalines 171 and receiving image signals from an external device. The drainelectrodes 175 of TFTs are separated from the data line units 171, 173and 179 and located opposite the source electrodes 173 with respect tothe gate electrodes 123 or TFT portions of the semiconductor layer 154.The data lines 171 for neighboring blue pixel columns B1 and B2 have aplurality of second pad connections 172 protruded from the their endsand having relatively large width. The first pad connections 122 areplaced close to the second pad connections 172.

The data wire 171, 173, 175 and 179 and the second pad connections 172may have a single-layered structure, a double-layered structure, or atriple-layered structure. In case they have a double-layered structure,it is preferable that one layer is made of a low resistance material,and the other layer is made of a material having a good contactcharacteristic with other materials.

The ohmic contact layer 163 and 165 has a function of lowering thecontact resistance between the underlying semiconductor layer 154 andthe overlying source and drain electrodes 173 and 175.

A protective layer 180 preferably made of silicon nitride is formed onthe data wire 171, 173, 175 and 179 and the semiconductor layer 154. Theprotective layer 180 has a plurality of contact holes 181 and 183exposing the drain electrodes 175 and the data pads 179, respectively,and the protection layer 180 and the gate insulating layer 140 have aplurality of contact holes 182 exposing the gate pads. Furthermore, theprotective layer 70 has a plurality of contact holes 184 exposing thesecond pad connections 172, and the protection layer 180 and the gateinsulating layer 140 have a plurality of contact holes 185 exposing thefirst pad connections.

A plurality of pixel electrodes 190 are formed on the protective layer180. The pixel electrodes 190 receive image signals from the TFTs andgenerate electric fields together with a common electrode formed on theupper panel. The pixel electrodes 190 are made of a transparentconductive material such as indium tin oxide (ITO) and indium zinc oxide(IZO). The pixel electrodes 190 are physically and electricallyconnected to the drain electrodes 175 of the TFTs provided at theneighboring pixel rows through the contact holes 181 to receive imagesignals. The pixel electrodes 190 overlap previous gate wire components121 a, 121 b, 123, 125 and 127 for transmitting scanning signals to theTFTs provided at the previously adjacent pixel row to form storagecapacitors. In case the desired storage capacitance is not obtained, astorage wire may be formed in a separate manner.

The pixel electrodes 190 for the blue pixels B1 and B2 in theneighboring pixel rows are connected to each other through first andsecond connections 901 and 902. The pixel electrodes 82 for a pair ofblue pixels B1 or B2 connected to each other are connected to a TFT. TheTFTs for the blue pixels B1 and B2 in two adjacent pixel rows arealternately provided in the two pixel rows. Therefore, on the area B,the second connection 902 overlaps the previous gate line 121 a and 121b. However, on the area B, the first connection 901 interconnecting thepixel electrodes 190 for the blue pixels B1 overlap the gate line 121 afor transmitting gate signals to the pixels at the pixel rowcorresponding thereto.

The overlapping of the first connections 901 and the gate line 121 amakes parasitic capacitance causing kick-back voltage, which reduces thepixel voltages applied to the relevant pixel electrodes 190 andgenerates brightness difference between the neighboring blue pixelcolumns.

In order to minimize the problem, in the configuration according to thefirst embodiment of the present invention that the storage capacitanceis made by the overlapping of the pixel electrodes 190 and the previousgate wire components 121 a, 121 b, 123, 125 and 127, the storagecapacitance required to be kept uniform. For this purpose, theoverlapping area between the first connection 901 and the gate line 121a on the area A is required to be optimized such that the parasiticcapacitance due to the overlap thereof be equal to or less than 5% ofthe sum of the liquid crystal capacitance and the storage capacitance ofthe relevant pixels. The reason is that if the parasitic capacitancebetween the first connection 901 and the gate line 121 a exceeds 5% ofthe total capacitance of the liquid crystal capacitance and the storagecapacitance of the relevant pixels, the kick-back voltage is increasedby equal to or higher than 1V so that the brightness difference betweenthe pixels is serious.

Meanwhile, a plurality of subsidiary gate pads 95 and a plurality ofsubsidiary data pads 97 formed of the same layer as the pixel electrodes190 are provided but they are optional. The subsidiary pads 95 and 97are connected to the gate pads 125 and the data pads 179 through thecontact holes 182 and 183 of the protective layer 180 and the gateinsulating layer 140, respectively.

A plurality of third pad connections 903 formed of the same layer as thepixel electrodes 190 are provided to electrically interconnect the datalines 171 for transmitting data signals to the neighboring blue pixelcolumns B1 and B2 to one data pad 179. The two second pad connections172 connected to the data lines 171 for transmitting data signals to thetwo neighboring blue pixel columns B1 and B2 as well as the first padconnections 122 positioned close thereto are connected to the third padconnections 903 through the contact holes 184 and 185 exposing them,respectively. The third pad connections 903 cross over the data lines171 for the neighboring red and green pixels R and G in an insulatingmanner while electrically interconnecting the two data lines 171 for theneighboring blue pixels to one data pad 179.

Since the data lines 171 for the neighboring blue pixels B1 and B2 areconnected to one data pad 179 using the first to the third padconnections 122, 172 and 903, an additional load resistance may be madeduring the transmission of the data signals due to the contactresistance at the contact holes 184 and 185 and the wire resistance ofthe first to the third pad connections 122, 172 and 903. It ispreferable that the additional load resistance generated by the additionof the connections is equal to or less than 20% of the total loadresistance of the data lines 171. The reason is that if the additionalload resistance exceeds 20% of the total load resistance of the datalines 171, the charging capacity of the pixels becomes reduced by anamount equal to or larger than 5%, and this deteriorates the displaycharacteristic.

Meanwhile, although the third pad connections 903 for interconnectingthe data lines for transmitting the data signals to the two blue pixelsB1 and B2 to one pad are formed of the same layer as the pixelelectrodes 190 in the structure shown in FIGS. 1 to 3, only the secondpad connections may be used for that purpose. The structure of suchconnections will be now described with reference to FIGS. 4 and 5.

FIG. 4 is a layout view of a configuration for connecting the data linesfor transmitting data signals to neighboring two blue pixels B1 and B2to one pad in a TFT array panel for an LCD according to a secondembodiment of the present invention, and FIG. 5 is a sectional view ofthe configuration shown in FIG. 4 taken along the line V-V′. Most of thestructure is the same as those of the first embodiment, and hence, adetailed view thereof is omitted.

As shown in FIGS. 4 and 5, two first pad connections 122 forinterconnecting two data lines 171 for neighboring two blue pixels areconnected to each other through a connecting member 124. A gateinsulating layer 140 has a plurality of contact holes 141 exposingrespective first pad connections 122. Two second pad connections 172connected to the respective data lines 171 for transmitting data signalsto the neighboring two blue pixels are connected to the first padconnections 122 through the contact holes 141 such that the two datalines 171 are electrically connected to each other.

Although a TFT array panel for a transmissive LCD including pixelelectrodes 190 made of transparent conductive material such as ITO andIZO is exemplified, a reflective conductive material such as Al, Alalloy, Ag and Ag alloy may be used for the pixel electrodes 190.

The above-described configuration according to the embodiment of thepresent invention, which is similar to the PenTile Matrix pixelarrangement, easily displays a circle and a diagonal such that a letteror a figure can be exactly displayed. Therefore, the resolution of theUXGA degree can be realized by using the pixel arrangement of SVGA andthe number of the data pads 179 is decreased. In this way, the number ofhigh cost data driving ICs can be decreased to minimize the costinvolved in designing the display device.

Furthermore, since the data lines for transmitting the data signals tothe blue pixels have the same shape as the data lines for transmittingthe data signals to the red and green pixels, non-uniformity of thedisplay characteristic is prevented. The desired storage capacitance isobtained by the overlapping of the previous gate lines and the pixelelectrodes, and simultaneously, the parasitic capacitance due to theoverlapping of the connections and the gate lines corresponding theretois optimized so that the storage capacitance can be formed in a uniformmanner. In addition, the data lines for transmitting data signals to thered or green pixels are spaced apart from each other with interposingthe unit pixels so that the possible short circuit between theneighboring data lines can be prevented. Furthermore, since theneighboring blue pixels are driven by one driving IC, the display devicecan have an optimized size and repair lines for repairing thedisconnections or short-circuiting of the signal wire can be easilyformed at the periphery of the display area.

Although the first embodiment of the present invention forms storagecapacitance by overlapping the pixel electrodes with the gate lines, aseparate storage wire may be introduced for that purpose.

A method of driving the above-described LCD will be now described indetail.

The LCD may be driven such that the image signals transmitted to thepixel electrodes are required to be repeatedly alternated from positiveto negative and vice versa with respect to the common voltage forpreventing the liquid crystal from being deteriorated, and the drivingtechnique is called the “inversion.” When the polarity inversion of thepixels is non-uniform, the image signals transmitted to the pixelelectrodes are seriously distorted to generate flicker, therebydeteriorating the image quality of the LCD. In order to solve theproblem, in a PenTile Matrix pixel arrangement including red, blue andgreen pixel columns arranged in sequence, the data lines for nearestblue pixel columns or next nearest blue pixel columns are connected toone pad, and the data lines for the neighboring red and green pixelcolumns cross each other to transmit the image signals. Thisconfiguration will be now described with reference to the accompanyingdrawings.

FIGS. 6 to 8 illustrate inversion schemes and connections of signallines therefor of an LCD according to third to fifth embodiments of thepresent invention. In the figures, the symbol “•” indicates the positionof TFTs of blue pixels arranged along a column direction, and thesymbols “+” and “−” indicate the polarities of the pixel voltages (orimage signals) applied to pixel electrodes with respect to a commonvoltage of a common electrode.

As shown in FIGS. 6 to 8, with the LCDs according to the third to thefifth embodiments of the present invention, red, green and blue pixelsR, G and B are sequentially arranged in the row direction, and the redand green pixels R and G are alternately arranged in the columndirection. The blue pixels B are disposed between the neighboring redand green pixel columns R and G and arranged every two pixel rows. Thefour red and green pixels surrounding a blue pixel B are disposedopposite each other with respect to the blue pixel B.

In an LCD according to the third embodiment of the present inventionshown in FIG. 6, an (n+4)-th data line 171 for blue pixels iselectrically connected to an (n+1)-th data line 171 for blue pixels suchthat an (n+4)-th, blue pixel column receives image signals through adata pad connected to the (n+1)-th data line 171. An (n+7)-th data line171 for blue pixels is electrically connected to an (n+10)-th data line171 for blue pixels such that an (n+7)-th, blue pixel column receivesimage signals through a data pad connected to the (n+10)-th data line171. Furthermore, an (n+5)-th data line 171 for green pixels crosses the(n+6)-th data line 171 for red pixels such that they transmit imagesignals to an (n+6)-th, green pixel column and an (n+5)-th, red pixelcolumn, respectively.

When the LCD having the above connection configuration is subject to dotinversion in the column and row directions, it shows a regularity of•••, +++, −−−, +−+, −+−, ••• in the row direction over the entire areaof the liquid crystal panel assembly as shown in FIG. 6.

In an LCD according to the third embodiment of the present inventionshown in FIG. 7, an (n+7)-th data line 171 for blue pixels iselectrically connected to an (n+1)-th data line 171 for blue pixels suchthat an (n+7)-th, blue pixel column receives image signals through adata pad connected to the (n+1)-th data line 171. An (n+10)-th data line171 for blue pixels is electrically connected to an (n+4)-th data line171 for blue pixels such that an (n+10)-th, blue pixel column receivesimage signals through a data pad connected to the (n+4)-th data line171. Furthermore, an (n+8)-th data line 171 for green pixels crosses the(n+9)-th data line 171 for red pixels such that they transmit imagesignals to an (n+9)-th, green pixel column and an (n+8)-th, red pixelcolumn, respectively.

When the LCD having the above connection configuration is subject to dotinversion in the column and row directions, it shows a regularity of•••, +++, −+−, ••• in the row direction over the entire area of theliquid crystal panel assembly as shown in FIG. 7.

In an LCD according to the third embodiment of the present inventionshown in FIG. 8, an (n+10)-th data line 171 for blue pixels iselectrically connected to an (n+1)-th data line 171 for blue pixels suchthat an (n+10)-th, blue pixel column receives image signals through adata pad connected to the (n+1)-th data line 171. An (n+7)-th data line171 for blue pixels is electrically connected to an (n+4)-th data line171 for blue pixels such that an (n+7)-th, blue pixel column receivesimage signals through a data pad connected to the (n+4)-th data line171. Furthermore, an (n+8)-th data line 171 for green pixels crosses the(n+9)-th data line 171 for red pixels such that they transmit imagesignals to an (n+9)-th, green pixel column and an (n+8)-th, red pixelcolumn, respectively.

When the LCD having the above connection configuration is subject to dotinversion in the column and row directions, it shows a regularity of•••, +++, −+−, +−+, −−−, ••• in the row direction over the entire areaof the liquid crystal panel assembly as shown in FIG. 8.

The dot inversion of an LCD according to the fourth embodiment of thepresent invention makes the regularity of •••, +++, −+−, ••• in the rowdirection, but makes a frame inversion for the blue pixels along the rowdirection to generate flicker. In order to solve the problem, columninversion or double-dot inversion is applied

FIGS. 9 and 10 illustrate column inversion and double-dot inversion forthe LCD according to the fourth embodiment of the present invention.

As shown in FIG. 9, the column inversion for the LCD according to thefourth embodiment of the present invention causes a dot inversion forthe blue pixels in the row direction, thereby improving the displaycharacteristic.

As shown in FIG. 10, a double-dot inversion causes the blue pixels toshow a dot inversion both in the column direction and in the rowdirection.

Meanwhile, when the data lines 171 cross each other to cross-transmitthe image signals to the neighboring red and green pixel columns in theLCDs according to the third to the fifth embodiments of the presentinvention, it is preferable that a data line crossing member is formedof the same layer as the data wire (in relation to the first and thesecond embodiments of the present invention), the gate wire (in relationto the first and the second embodiments of the present invention), andthe pixel electrode (in relation to the first and the second embodimentsof the present invention). This will be described with reference toFIGS. 11 and 12.

FIGS. 11 and 12 are layout views of a cross-connection of data lines foran LCD according to the third to the fifth embodiments of the presentinvention. Reference numeral 124 indicates a first crossing memberformed of the same layer as a gate wire, reference numeral 710 indicatea second crossing member formed of the same layer as a data wire, andreference numeral 720 indicates a third crossing member formed of thesame layer as the pixel electrode.

As shown in FIG. 11, an (n+5)-th data line and an (n+6)-th data line, oran (n+8)-th data line and an (n+9)-th data line for transmitting imagesignals to the red and the green pixel columns are formed on a TFT arraypanel for the LCD according to the third to the fifth embodiments of thepresent invention. The data lines 171 proceed parallel to each other.Data pads 179 are cross-connected to the data lines 171 in a crossedmanner. The second crossing member 710 is bent such that it electricallyconnects the (n+5)-th data line and the (n+8)-th data line to a (n+6)-thdata pad and a (n+9)-th data pad, respectively. The first and the thirdcrossing members 124 and 720 connect the (n+6)-th data line and the(n+9)-th data line to a (n+5)-th pad and a (n+8)-th data pad,respectively. The first crossing member 124 is formed of the same layeras the gate wire and curved such that it crosses the second crossingmember 710. The third crossing member 720 electrically connects thefirst crossing member 124 to the data line 171 through a contact hole910 formed at the gate insulating layer (140 shown in FIG. 2) or theprotective layer (180 shown in FIG. 2).

FIG. 12 illustrates a configuration that the second crossing member 710shown in FIG. 11 is modified to become similar to the first crossingmember 124 for obtaining uniform contact resistance at the data linecross-connection. As shown in FIG. 12, the second crossing member 710connects the data line 171 to the third crossing member 720 connected tothe data pad 179 through a contact hole 910 formed at the gateinsulating layer (140 shown in FIG. 2) or the protective layer (180shown in FIG. 2).

The data lines for transmitting image signals to the red and the greenpixel columns including the data line cross-connections includes contactportions with the first, second or third crossing members so that theyhave line resistance different from other data lines. This is liable toexert a bad influence to the display characteristic of the LCD. In orderto solve the problem, the difference in the line resistance of the datalines is required to be minimized. For this purpose, it is preferable toprovide a connection at each data line. This will be now described withreference to FIG. 13.

FIG. 13 is a layout view of connections and cross-connections of datalines on the TFT panel for the LCD according to the third to the fifthembodiments of the present invention.

As shown in FIG. 13, each data line 171 is connected to a data pad 179through a first connection wire 126 formed of the same layer as a gatewire, and the second connection wire 720 formed of the same layer aspixel electrodes.

In the above structure, each data line 171 is connected to thecorresponding data pad through two contact portions so that the datalines 171 have uniform linear resistance to prevent the deterioration ofthe display characteristic.

Meanwhile, the LCD with the above-described PenTile Matrix pixelarrangement according to the embodiments of the present invention issubject to rendering for realizing high resolution. The rendering refersto a technique that individually drives red, green and blue pixels afterdistributing a luminance of a pixel to neighboring pixels for finelydisplaying an oblique line or a curved line and increasing theresolution.

However, a black matrix disposed between the pixels for preventing lightleakage, which is displayed in black, causes phase error since the areaoccupied by the black matrix is not considered in rendering. In order tosolve the problem, the width of the black matrix is required to beminimized to minimize the area occupied by the black matrix.

For this purpose, the size of the pixel electrode 190, 190R, 190G, 190B1and 190B1 (referring to FIGS. 1 and 6) is required to be maximized suchthat edges of the pixel electrode overlap the gate lines 121 and thedata lines 171. In the structure shown in FIG. 1, each gate line 121includes only a single line and the gate line connection 127 is omitted,and a separate storage wire may be additionally introduced as shown inFIG. 2. However, when the pixel electrodes 190, 190R, 190G, 190B1 and190B1 (as shown in FIGS. 1 and 6) overlap the data lines 171 withinterposing a passivation layer 180, a parasitic capacitance generatedtherebetween may distort the data signal transmitted through the dataline 171. In order to solve the problem, the protective layer 180 ispreferably made of an acryl-based organic insulating material having alow dielectric constant and an excellent flattening characteristic, or achemical vapor deposited insulating material having a low dielectricconstant equal to or less than 4.0 such as SiOC or SiOF. Consequently,the size of the pixel electrode 190, 190R, 190G, 190B1 and 190B1 (asshown in FIGS. 1 and 6) can be maximized to secure a high aperture ratioand to minimize the width of the black matrix for preventing lightleakage between the pixels. The minimized black matrix area increasesthe brightness and thus improves the color reproduction, therebyenabling precise rendering.

Meanwhile, the structures of the TFT array panel for the LCD accordingto the first to the fifth embodiments of the present invention suggestvarious kinds of wire configurations or wire connection configurationsfor interconnecting the pixel electrodes for blue pixels in theneighboring pixel rows, for connecting the data lines for theneighboring blue pixels to one pad, and for performing the inversion. Adata pad is connected to each data line for simplifying the structure ofthe data wire or for facilitating inversion or rendering. This will benow described with reference to the figures.

FIG. 14 is a layout view of an LCD with a PenTile Matrix pixelarrangement according to a sixth embodiment of the present invention.The sectional structure or the pad structure is almost the same as thoserelated to the first to the third embodiments of the present invention,and hence, the description thereof will be omitted while making adescription for the pixel layout.

Referring to FIG. 14, an LCD with a PenTile Matrix pixel arrangementaccording to a sixth embodiment of the present invention includes red,blue and green pixels R, B and G arranged in a matrix. The red, blue andgreen pixels R, B and G are sequentially arranged in a row direction.One kind of pixel columns include the red and green pixels alternatelyarranged, and the other kind of pixel columns include only the bluepixels B. In a pixel row, the red and the green pixels R and G arestanding at both sides of the blue pixel B.

As shown in FIG. 14, a plurality of gate lines (or scanning lines) 121for carrying scanning signals or gate signals, which extend in the rowdirection, are provided at the respective pixel rows. A plurality ofdata lines 171 for carrying data signals are provided at the respectivepixel columns. The data lines 171 proceed in the column direction suchthat they cross over the gate lines 121 to define pixel areas and areinsulated from each other.

Each pixel area has a shape of rectangle having 2:3 horizontal tovertical ratio. The ratio is determined in consideration that two bluepixels form one dot in association with the pair of red and green pixelsarranged at the left and the right sides thereof in an alternate manner.

Unlike the LCDs according to the first to the fifth embodiments of thepresent invention, the LCD according to the sixth embodiment of thepresent invention provides the pixel arrangement for the blue pixels,which is the same as that for the red and the green pixels. That is, aTFT is formed at each cross point of the gate lines 121 and the datalines 171. The TFT includes a gate electrode 123 connected to the gateline 121, a source electrode 173 connected to the data line 171, a drainelectrode 175 facing the source electrode 173 with respect to the gateelectrode 123, and a semiconductor layer 154. A plurality of pixelelectrodes 190 are provided at respective blue pixels and electricallyconnected to the gate lines 121 and the data lines 171 through the TFTs.

Furthermore, unlike the structures related to the first and the secondembodiments of the present invention, a plurality of storage electrodelines 131 formed of the same layer as the gate lines 121 are provided.The storage electrode lines 131 proceed in the transverse direction suchthat they overlap the pixel electrodes 190 to form storage capacitors. Aplurality of contact holes 180 for connecting the pixel electrodes 190to the data wire are formed at a protective layer 180 (as shown in FIGS.1 and 2) on a plurality of drain electrodes 173. A data pad 179 isconnected to an end of each data line 171, receives image signals froman external device, and transmits them to the data line 171.

This structure facilitates the inversion since the data lines 172 fortransmitting the data signals to the blue pixels B easily receive thedata signals through their own data pads 179. Therefore, the LCD doesnot have a complicated wire configuration such as connections andcross-connections of the data wire unlike the structures related to thefourth and the fifth embodiments of the present invention, therebyrealizing uniform line resistance of the signal wire over the entirearea of the panel. Furthermore, since the data lines 175 for the bluepixels B are connected to their own data pads 179 for receiving theimage signals, the rendering is also easy. In addition, the LCD has theadvantages of the first to the third embodiments of the presentinvention.

A PenTile Matrix LCD with improved viewing angle according to a seventhembodiment of the present invention will be now described in detail.

FIG. 15 is a layout view of an LCD according to a seventh embodiment ofthe present invention, and FIG. 16 is a sectional view of the LCD shownin FIG. 15 taken along the line XVI-XVI′.

The LCD includes a TFT array panel, a color filter array panel, and aliquid crystal layer sandwiched between the panels.

The TFT array panel will be first described in detail.

As shown in FIGS. 15 and 16, a plurality of gate lines 121 are formed onan insulating substrate 110. The gate lines 121 proceed in a transversedirection, and a plurality of portions of each gate line 121 form aplurality of gate electrodes 123. A plurality of storage electrode lines131 and storage electrodes 133 connected thereto are formed on theinsulating substrate 110. The storage electrode lines 131 proceedsubstantially in the transverse direction but having some curves. Thestorage electrodes 133 connected to the storage electrode lines 131 havea shape of a closed loop.

A gate insulating layer 140 is formed on the gate wire 121 and 123 andthe storage electrode wire 131 and 133.

An amorphous silicon layer 154, an ohmic contact layer 163 and 165, anda data wire 171, 173 and 175 are sequentially deposited on the gateinsulating layer 140. The ohmic contact layer 163 and 165 is made ofamorphous silicon heavily doped with N-type impurities. The data wire171, 173 and 175 has substantially the same outline as the ohmic contactlayer 163 and 165, and the amorphous silicon layer 154 has substantiallythe same outline as the data wire 171, 173 and 175 except for TFTchannel portions. That is, the amorphous silicon layer 154 continuouslyproceeds across the channel portions, but the data wire 171, 173 and 175and the ohmic contact layer 163 and 165 are separated around the channelportions. Therefore, the data wire is considered to have atriple-layered structure including the amorphous silicon layer 154, theohmic contact layer 163 and 165, and the metal layer 171, 173 and 175.

The data wire 171, 173 and 175 includes a plurality of data lines 171, aplurality of source electrodes 173, and a plurality of drain electrodes175. The source electrodes 173 are connected to the data lines 171, andthe drain electrodes 175 faces the source electrodes 173 on the gateelectrodes 121 with being spaced apart from each other by apredetermined distance.

A protective layer 180 having a plurality of contact holes 181, 184 and185 is formed on the data wire 171, 173 and 175.

A plurality of pixel electrodes 190 are formed on the protective layer180. Each pixel electrode 190 has a cutout 191 proceeding from the rightedge of the pixel electrode 190 toward the left edge thereof andbisecting the pixel electrode 190 into upper and lower halves.

The color filter array panel will be now described in detail.

A black matrix 220 is formed on a transparent substrate 210, and red,green and blue color filters 230 are formed on the black matrix 220. Anovercoat layer 250 is formed on the color filters 230, and a commonelectrode 270 having a plurality of cutouts 271 is formed on theovercoat layer 250. The cutout 271 of the common electrode 270 has ashape of a capital letter V. The cutout 271 further partitions the pixelarea bisected by the cutout 191 of the pixel electrode 190 to form fourquarters. The cutout 271 is curved at an angle of about 90°, and twobranches thereof make an angle with the gate line 121 by about 45° or135°.

The cutout 271 largely overlaps the drain electrode 175, at least at thecontact hole area. That is, the TFT array panel is designed such thatthe drain electrode 175 overlaps the cutout 271 after the TiF arraypanel is assembled with the color filter array panel. The overlap schemeof the cutout 271 and the drain electrode 175 is to minimize thereduction of the aperture ratio.

A liquid crystal layer is sandwiched between the TFT array panel and thecolor filter array panel. The liquid crystal molecules contained in theliquid crystal layer are aligned perpendicular to the substrates 110 and210 in absence of electric field between the pixel electrode 190 and thecommon electrode 270.

Each pixel area has a shape of a rectangle having the ratio of ahorizontal length (x) to a vertical length (y) equal to 2:3. The ratiois determined in consideration that two blue pixels form one dot inassociation with the pair of red and green pixels arranged at the leftand the right sides thereof in an alternate manner.

The cutout 271 of the common electrode 270 and the cutout 191 of thepixel electrode 190 partition a pixel region into four domains havinguniform orientations of the liquid crystal molecules. The mutualcompensation of the four domains gives a wide viewing angle.

In the above-described structure, the PenTile Matrix driving provideshigh resolution images, and at the same time, the control of thearrangement of the liquid crystal molecules by the cutouts of the pixelelectrode and the common electrode provides wide viewing angle.

As described above, with the inventive PenTile Matrix pixel arrangement,the high resolution expression capacity being advantageous in displayinga letter or a device is exerted while minimizing the design cost. Thedata lines for transmitting signals to the blue unit pixels are linearlyformed with the same shape as other signal wire components so that thedisplay characteristic can be obtained in a uniform manner. Furthermore,the storage capacitance can be obtained using the previous gate lineswhile optimizing the parasitic capacitance due to the overlapping of theconnections and their own gate lines. In this way, the storagecapacitance can be obtained in a uniform manner. In addition, the datawire and the gate wire are spaced apart from each other with apredetermined distance while preventing the neighboring signal wirecomponents from being short-circuited. The data driving ICs may bearranged at a one area with respect to the display area using the padconnections while optimizing the size of the display device. In thiscase, the repair lines may be easily formed at the periphery of thedisplay area to repair the possible disconnection or theshort-circuiting of the signal wire components.

Furthermore, the inversion with uniform polarities can be made throughcross-applying the image signals to the red and the green pixel columnneighbors between the two blue pixel columns electrically connected toeach other. The neighboring blue pixel columns move by ½ pixel so thatthe uniform inversion can be made using the previous gate line or therelevant data line at all the blue pixels, while obtaining a uniformstorage capacitance. The gate line, the data line and the pixelelectrode overlap each other while interposing a low dielectricinsulating material, thereby obtaining a maximum aperture ratio. In thisway, the rendering driving technique is effectively applied to preciselyexpress the image at high resolution. The image signals are applied tothe data lines through the respective data pads, and hence, it is notrequired to make a complicated signal wire structure or a wireconnection configuration. In this way, the rendering driving or theinversion can be made in an easy manner. Furthermore, the domainpartitioning based on the cutouts makes it possible to obtain wideviewing angle.

1. A thin film transistor array panel comprising: an insulatingsubstrate; a plurality of gate lines carrying scanning signals, formedon the insulating substrate, and proceeding in a transverse direction; aplurality of data lines carrying image signals, proceeding in alongitudinal direction to intersect the gate lines, and insulated fromthe gate lines; a plurality of pixel electrodes formed in respectivepixels defined by intersections of the gate lines and the data lines andreceiving the image signals; and a plurality of thin film transistorsformed in the pixels and having gate electrodes connected to the gatelines, source electrodes connected to the data lines, and drainelectrodes connected to the pixel electrodes, wherein a ratio ofhorizontal to vertical of each pixel is substantially equal to 2:3. 2.The thin film transistor array panel of claim 1, wherein the pixelelectrodes overlap previous gate lines for transmitting the scanningsignals to previous adjacent pixel rows to form storage capacitors. 3.The thin film transistor array panel of claim 1, further comprising aplurality of storage electrode lines separated from the gate lines,formed of the same layer as the gate lines, and overlapping the pixelelectrodes to form storage capacitors.
 4. The thin film transistor arraypanel of claim 1, further comprising a protective layer formed betweenthe pixel electrodes and the gate lines and the data lines, made ofacryl-based organic insulating material or chemical vapor depositedinsulating material having a dielectric constant equal to or less than4.0, and having a plurality of contact holes for electrically connectingthe pixel electrodes to the drain electrodes.
 5. The thin filmtransistor array panel of claim 1, wherein the data lines have atriple-layered structure including an amorphous silicon layer, an ohmiccontact layer, and a metallic layer.
 6. The thin film transistor arraypanel of claim 1, wherein the pixel electrodes have cutouts.
 7. The thinfilm transistor array panel of claim 1, wherein a data pad for receivingdata signals from an external device is connected to each data line. 8.A liquid crystal display comprising: a first insulating substrate; aplurality of gate lines carrying scanning signals, formed on the firstinsulating substrate, and proceeding in a transverse direction; aplurality of data lines carrying image signals, proceeding in alongitudinal direction to intersect the gate lines, and insulated fromthe gate lines; a plurality of pixel electrodes formed in respectivepixels defined by intersections of the gate lines and the data lines andreceiving the image signals; and a plurality of thin film transistorsformed in the pixels and having gate electrodes connected to the gatelines, source electrodes connected to the data lines, and drainelectrodes connected to the pixel electrodes; a second insulatingsubstrate facing the first insulating substrate; a black matrix formedon the second insulating substrate; red, green and blue color filtersformed on the black matrix and provided at the respective pixels; acommon electrode formed on the color filters; and a liquid crystal layersandwiched between the pixel electrode and the common electrode, whereinred, blue and green pixels are sequentially arranged in a row direction,the red and the green pixels are alternately arranged in a columndirection, the blue pixels are repeatedly arranged in the columndirection, four red and green pixels surrounding adjacent two bluepixels in neighboring two pixel rows face each other, and a ratio ofhorizontal to vertical of each pixel is equal to 2:3.
 9. The liquidcrystal display of claim 8, wherein each pixel electrode has a firstcutout, the common electrode has a plurality of second cutouts, and eachpixel is partitioned into a plurality of domains by the first and thesecond cutouts.
 10. The liquid crystal display of claim 9, whereinliquid crystal molecules contained in the liquid crystal layer arealigned perpendicular to the first and the second substrates in absenceof electric field between the pixel electrodes and the common electrode.11. The liquid crystal display of claim 9, further comprising aprotective layer formed between the pixel electrodes and the gate linesand the data lines and having a plurality of contact holes forelectrically connecting the pixel electrodes to the drain electrodes,the drain electrodes overlapping the second cutouts at least at thecontact holes.